Hypertension in pregnancy is, both in man and in other mammals, associated with impaired fetal growth. In man it is frequently associated with a syndrome of proteinuria and edema which is termed "toxaemia of pregnancy" or preeclampsia These pregnancies are complicated by insufficiency and fetal growth retardation. Current therapy is essentially restricted to common anti-hypertensive agents and bed rest which, while reducing the risk of hypertensive crises in the mother, do not correct the fetal growth retardation and reduce the consequent risk of fetal death, stillbirth and the neonatal complications of intrauterine growth retardation. The essence of this invention is that we have found that the administration of IGF-1 in pregnant hypertensive mammals reduces maternal blood pressure and improves placental function and fetal development.
We have previously disclosed that the administration of IGF-1 through part or whole of pregnancy to a maternal mammal overcomes maternal constraint on fetal growth (IGF-1 in Pregnancy: PCT Europe 91912874.4, USA 07/969229, Japan 3-511969, Australia 82052/91, Canada 2087030). We have observed such administration of IGF-1 promoting fetal growth and placental function. However there is nothing in the prior art that would have led us to conclude that there would be a lowering effect on blood pressure. Elsewhere we have disclosed that in non-pregnant animals IGF-1 promotes cardiac output (Ambler et al J Cardiovascular Research 27 1368-1373 1993) and this is associated with maintenance of blood pressure.
In pregnant mammals with hypertension and a predisposition to give birth to growth retarded fetuses with disproportionately large placentas, we have now observed that IGF-1 administration to the mother reverses these changes.